Abstract: Sera which were collected from 1941 healthy children in Changsan county during 1982 to 1996 had been detected by using ELISA.The results indicated that GMT of N.meningitis (Nm) sreogroup A antibody collected from pre epidemic period was significantly lower than those from epidemic period.Positive rates and GMTs of Nm.serogroup A antibody in ≤2 age group were significantly lower than those in 6～9 and 10～15 age group.The GMT of Nm serogroup B antibody was lower than that of Nm serogroup A but there was no statistic significance between them.In some age groups,the antibodies titer of serogroup B and A had lineat correlation.The antibodies GMT of carriers of Nm serogroup A and B were not significantly higher than those of non - carriers. There was no linear correlation between the GMTs of Nm serogroup A antibodies and morbidity of epidemic meningitis during 1982 to 1996.These results suggested that epidemic meningitis surveillance should be done in pre-epidemic period.When sera antibodies were detected by ELISA bactericidal antibodies in a few sampling specimens should also be tested as a control.